Dual MBC

[Mutmatt]

Running it this way would cause MORE BOOST. It would not cause less spike. A boost controller works in this way. It leaks air causeing the wastegate to be fooled into thinking that full boost has not yet been reached. If you put two mbcs on and turn them both the same it would give you more boost. The only way to rid yourself of spike is to get an EBC that has spike control on it. Do not do this it is a bad idea and a waste of money.

totally the same thing i was thinking... and just to clarify this thread was started stating that two MBC's were put on the same vac. line and set to the desired level to decrease boost spike, NOT correct statement! This is not a dual stage boost controller thread. As far as getting rid of boost spike... it is difficult, if not impossible. A very well engineered MBC with quality parts will get you closer to that goal (that means spend more money to get it to work right) or a nice EBC. So basicly spend more get more, spend nothing, get nothing...

 

[Blake]

totally the same thing i was thinking... and just to clarify this thread was started stating that two MBC's were put on the same vac. line and set to the desired level to decrease boost spike, NOT correct statement! This is not a dual stage boost controller thread. As far as getting rid of boost spike... it is difficult, if not impossible. A very well engineered MBC with quality parts will get you closer to that goal (that means spend more money to get it to work right) or a nice EBC. So basicly spend more get more, spend nothing, get nothing...

And you sir are correct on all accounts.

 

[jeffmsp]

never had a problem adjusting the wastegate and many people just put a carb spring on it to adjust it. That way worst case scenerio is that you go back to stock boost if the spring breaks or falls off kinda thing. $5 mbc that works or just adjust it yourself. Or like they are saying spend the cash on a ebc.

btw where you tap your wastegate vac source has a impact on how the boost spikes, the reason its tapped from the intake manifold from the factory is to gain the spool. At such low boost levels with the restrictive factory equipment it doesnt spike. Tap the wastegate vac line before the intercooler and the spiking problem is greatly reduced. My buddy is running with his wastegate vac source on the turbo to IC pipe and had almost no diff in spool but was able to get rid of spike. The reason it spikes is because it takes a little bit for the compressed air to go through the piping and intercooler then into the intake manifold where it is met by the wastegate actuator vac line. So for the split second it takes to get there the turbo is overboosting since the wastegate hasnt yet actuated, then boosts gets to the intake manifold and the wastegate line gets the boost and the wastegate opens. I bet changing your vac source will eliminate the problem and you can use your current mbc without spike.

 

[Maxx Mazda]

I just spoke with Dana (KoolDino) on the phone and we got to talking about boost controllers. He's boosting about 22 psi or something liek that right now, and all on a JoeP MBC. That's right, an MBC. I'm also running the JoeP, and I never spike at all, even when set at like 8psi, or even 10 or 12. It would always go right to the set boost level and then maintain, very well. I'm wondering if spikes are caused by the wastegates themselves, and NOT the boost controllers.

You see, an EBC would constantly regulate boost if the wastegate was spiking, but an MBC would not react to that like the EBC does. Take your boost controller right out and see if it still spikes.

 

[Drumfreak]

I just spoke with Dana (KoolDino) on the phone and we got to talking about boost controllers. He's boosting about 22 psi or something liek that right now, and all on a JoeP MBC. That's right, an MBC. I'm also running the JoeP, and I never spike at all, even when set at like 8psi, or even 10 or 12. It would always go right to the set boost level and then maintain, very well. I'm wondering if spikes are caused by the wastegates themselves, and NOT the boost controllers.

You see, an EBC would constantly regulate boost if the wastegate was spiking, but an MBC would not react to that like the EBC does. Take your boost controller right out and see if it still spikes.

I totally agree with you that the wastegates are mostly the problems with the MSP's. The only things you can do is try different MBC's to see how they work or put in softer springs into them which I did with my boost science and that helped a lot. Without my mbc in I do see a spike. Our turbos are great for spool time but run risk of spiking. Just put in a gt28rs. You might blow up the motor but at least you wont have a boost spike.

 

[GhostMercury]

would putting in one of the 50 dollar i think its awr waste gates help?

 

[justa4banger]

Spikes are due to Boost controllers (diff.types) wastegates and exhaust housing size. If your particular housing is to small for what you are trying to do with it then it can spike bad

My other turbo car has a hybrid turbo (internal gate) the exhaust housing was a .48 ar, Boost spikes were as much as 6 psi. I ran it set for 20 psi.
dyno made 243hp and 320trq. changed the exhaust housing ONLY to a .63 ar and redynod.
Boost spikes were gone and i made 275 whp and 308trq. trq went down due to the lack of overboost on the initial hit of the turbo.

 

[BlueBeast22]

I just spoke with Dana (KoolDino) on the phone and we got to talking about boost controllers. He's boosting about 22 psi or something liek that right now, and all on a JoeP MBC. That's right, an MBC. I'm also running the JoeP, and I never spike at all, even when set at like 8psi, or even 10 or 12. It would always go right to the set boost level and then maintain, very well. I'm wondering if spikes are caused by the wastegates themselves, and NOT the boost controllers.

You see, an EBC would constantly regulate boost if the wastegate was spiking, but an MBC would not react to that like the EBC does. Take your boost controller right out and see if it still spikes.

See, Im running a JoeP MBC set to 9psi and mine spikes up to 11-12 and sometimes will cause a small fuel cut if colder outside. So im not sure if I just got a crappy one or what.

 

[Maxx Mazda]

See, Im running a JoeP MBC set to 9psi and mine spikes up to 11-12 and sometimes will cause a small fuel cut if colder outside. So im not sure if I just got a crappy one or what.

Have you got the old school version, or the new twist type one? I'm runnign the new one.

 

[Kansei]

the twist one worries me because to turn down the boost you are loosening it.. and it comes apart into two pieces if you go too far, leaving you with MAX BOOST YO

 

[Maxx Mazda]

Once you get it totally "loose" there's still like turns before it comes apart.